I think it comes from the library implementing time/gmtime (i think c runtime) :)

I'd try to compare results with DateTime

On some Windows machine I get 

Timezone: 

2008-03-30T00:59:59       UTC    1206838799    BST    1206867599
2008-03-30T01:00:00       UTC    1206838800    BST    1206867600
2008-03-30T01:00:01       UTC    1206838801    BST    1206867601
2008-03-30T02:00:00       UTC    1206842400    BST    1206871200
2008-10-26T00:59:59       UTC    1224982799    BST    1225011599
2008-10-26T01:00:00       UTC    1224982800    BST    1225011600
2008-10-26T01:00:01       UTC    1224982801    BST    1225011601
2008-10-26T01:00:02       UTC    1224982802    BST    1225011602
2008-10-26T01:30:00       UTC    1224984600    BST    1225013400
2008-10-26T01:30:01       UTC    1224984601    BST    1225013401
2008-10-26T01:30:01       UTC    1224984601    BST    1225013401
2008-10-26T01:45:00       UTC    1224985500    BST    1225014300
2008-10-26T01:50:00       UTC    1224985800    BST    1225014600
2008-10-26T01:55:00       UTC    1224986100    BST    1225014900
2008-10-26T01:55:59       UTC    1224986159    BST    1225014959
2008-10-26T01:56:00       UTC    1224986160    BST    1225014960
2008-10-26T01:57:00       UTC    1224986220    BST    1225015020
2008-10-26T01:58:00       UTC    1224986280    BST    1225015080
2008-10-26T01:59:58       UTC    1224986398    BST    1225015198
2008-10-26T01:59:59       UTC    1224986399    BST    1225015199
2008-10-26T02:00:00       UTC    1224986400    BST    1225015200
2008-10-26T02:00:01       UTC    1224986401    BST    1225015201
2008-10-26T02:59:59       UTC    1224989999    BST    1225018799
2008-10-26T03:00:00       UTC    1224990000    BST    1225018800
2008-10-26T03:00:01       UTC    1224990001    BST    1225018801

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In reply to Re: Perl mktime/gmtime peculiarities (Inc. Testcase) [Cygwin/Windows] by Anonymous Monk
in thread Perl mktime/gmtime peculiarities (Inc. Testcase) [Cygwin/Windows] by NeilSaunders

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